Close to half of all children who remain at home with their permanent caregivers following a child welfare investigation (i.e., not placed into foster care) manifest high rates of mental health need, yet few engage or remain in mental health treatment (Burns et al., 2004; Lau & Weisz, 2003).This is particularly concerning as children from these child welfare involved families (CWIFs) manifest disproportionately high rates of behavioral difficulties (ACF, 2005; Burns et al., 2004). Lack of available child mental health service providers in inner-city communities (Asen, 2002) creates even greater obstacles to accessing treatment. The Multiple Family Group (MFG) service delivery model to reduce childhood disruptive behavior disorders (DBDs; Franco et al., 2008; Gopalan & Franco, 2009; McKay, et al., 1995; 1999; 2002; Stone, McKay, & Stoops, 1996) is currently being tested in an NIMH-funded effectiveness study. This model may be beneficial for CWIFs as an innovative, engaging mental health intervention that addresses inner-city service capacity limitations. Although preliminary data indicate that CWIFs manifest high engagement rates in MFGs, CWIFs have substantial needs (e.g., parental depression) which may exceed the MFG model's current capacities. As a result, the MFG model may require adaptation for CWIFs. Consequently, the goals of the proposed fellowship include (1) increasing the applicant's theoretical knowledge and methodological expertise in child mental health service and intervention science; (2) increasing theoretical knowledge in services for CWIFs and family-based treatment of childhood DBDs; and (3) preparing the applicant to develop and pilot a family-based mental health intervention for CWIFs to reduce childhood DBDs. The specific aims of the current application are met through two studies examining CWIF caregiver responses to the MFG model and identifying where modifications, if any, may be necessary. Using qualitative methods, Study #1 will identify CWIF caregiver perceptions of factors that influence service delivery (i.e., engagement, program helpfulness, relevance, and ability to stimulate motivation to make family- level changes), and recommendations for improvement. Study #2 involves quantitative, secondary data analyses to assess if CWIF status moderates the MFG treatment effect over time regarding (1) engagement and process characteristics of service delivery (i.e., relationship with service provider, relationships between MFG members, parental and youth motivation to address treatment goals, perceived barriers to treatment), (2) family-level outcomes and parent characteristics (i.e., parenting skills, family communication, within family support, and parent/child interaction, parent stress, parent depression, parent coping), and (3) youth-level outcomes (i.e., externalizing behavioral difficulties and functional capacities). Those outcomes where the MFG treatment effect is attenuated can be targeted for further revision when adapting the MFG model. Both studies will provide preliminary data used to develop and pilot a family-based mental health intervention to reduce child DBD's for CWIFs. Thus, mental health treatment may be improved for a diverse and vulnerable population.